The study was carried out using the system of accelerators (I-100, U-1.5, U-70). Ultra-precise equipment to position biological objects was applied. The dependency of melanoma B-16 cells survival on the dose of 12C ion irradiation was obtained. The carbon beam was studied within three main ranges: Bragg peak, areas before and after the peak. Dose dependence in the peak and in the area before the peak had a distinct linear pattern. In the distal part of the Bragg peak, linear-quadratic dependence was observed. Carbon ions RBE were 4.5, 1.7 and 2.4 for the peak, the areas before and after the peak, respectively.